Diaphragm for electrolytical cells



R. WALTER. DIAPHRAGM FOR ELECTROLYTICALVCELLS. APPLICATION FILED JAN-30.1918.

j} 11 w Patented 1960" 6; WEJL UNITED STATES RICHARD warren. or VILLAGE. AUSTRIA, nssrenon, BY MESNE ASSIGNMENTS, TO THE CHEMICAL FOUNDATION, 11m. A CORPORATION or DELAWARE.

DIAfHRAGM FOR ELEC TROLYTICAL CELLS.

Specification of Letters Patent.

"atcntcd 11cc. ti, 19921.

Application filed January 30, 1918. Serial No. 214,484.

To all whom it may concern:

lie it known that I. Rrcnann \VALTER. company director. subject of the German Cmpcror. residing at Villach, in the Empire of Austria. have invented certain new and useful Improvements in Diaphragms for Electrolyti -al Cells. (for which I have filed applications in Austria Dec. 19th. 1916, and in Germany June 26. 1917.) of which the following is a specification.

As well known. diaph'agms for electrolytical cells. which are made of ceramic or the like material. offer a resistance to the passage of the electric current that can only be overcome by a corresponding tension. 2'. 0., of electrical energy. Hence. as the resistance considerably increases in proportion to the wall-thickness of the diaphragm. this thickness should be as slight as possible. l p to the present. however. difficulties encountered in the process of manufacture. as also the amount of mechanical strength required, have raised p 'actically insurmountable barriers to this object being successfully attained.

The present invention has for-its object to satisfy the afore-indicated demand to the utmost extent possible.

In the accompanying drawing is shown, by way of example. an embodiment of the subject matter of the invention. wherein Figure 1 illustrates a cross-section of a diaphragm-plate of the kind hitherto in use, while Figs- 2 and 3 show cross-sections of plates made in accordance with the inven' tion; Figs. 1 and 5 being top-views of modified forms thereof. and Fig. 6 a cross-sectional view ot' a cylindrical cell.

An extremely effective reduction in the thickness of the diaphragm-wall will be ob tained by providing the constructional forms hitherto in use (Fig. 1) on either side with a series of staggered notches. and thus producing a corrugated configu 'ation (Figs. 2 and 3). so that all the lines of the current passing-through the plate will traverse a uniformly reduced thickness of the material in all directions.

Further. by suitably dimensioning this said configuration. it will be possible to obtain. in consequence of the reduced thickness. the same or even a greater moment of mechanical resistance than which it was possible to obtain by means of the uniform cross-section of the wall-thicknesses hitherto employed.

The mechani-al strength of the diaphragm. the wall-portion of which has thus been materially reduced. may be advantageously improved. if the notches or grooves. which may run in straight. broken. curved or retraced lines are arranged in symmetrically alternatin directions. as illustrated, for example. in l igs. l and as this allows favorable resistance to the bending strain of the plate. while any strains that may posslbly arise in the course of manufacture (particularly in the case of substances subjected to a burning or firing process) will be mutually compensated for.

In order to enable plates made in accordance with the present invention to be fixed in their place and packed in the same manner as that hitherto employed in connection with fiat plates it will be found practicable to surround the former on either side with a perfectly flat edge.

An essential advantage of the present novel form of construction moreover resides in the fact that. the external dimensions of the plates being the same. there is obtained. in consequence of the corrugated configuration of the plate. a larger diaphragm surface area: which fact produces. in addition to the diminution of the resistance resulting from the reduction in the wall-thickness. a further diminution of the resistance offered to the electric current.

Another advantage resides in the fact that. in particlular in the *ase or cylindrical cells of the kind shown in Fig. ti. a favorable influence may be exerted on the density of the current. this being a feature of vast importance in conneection with many electrolytical prm'esscs.

As Fig. 6 shows. cells of the said kind (which may easily be manufactured in manifold forms and shapes. say for example in presses by means of suitably profiled mouth-pieces) allow. to a high degree. an increase of current density by an effective reduction of the volume of the cell. while. simultanwusly. there is aii essential increase in the effective diaphragm surface area when tfllllptlltt'l with that of a cell of the kind hitherto employed. having the same diameter and a circular cross-section.

It is known that plates of sheet-metal, cardboard, and the like, with ribs or corrugations increase the breaking-strain. It has already been proposed to employ corrugated plates for commutators, where the plates are intended to insulate plates of opposite polarity supporting the active material. But in all these cases, the object of the corrugated plates is to prevent the passage of the electric current, whereas, on the contrary, diaphragms must be so formed as to permit the current to pass through.

Diaphragm-boxes for electrol tical purposes have likewise been manu hctured of flexible materials, such as parchment, asbestos-cardboard, and the like, and have been pressed between grille-shaped systems of parallelly arranged bars made of acid-proof materials, such as glass or orcelain. It has, moreover, been suggeste to manufacture cells of plastic asbestos and to provide the walls of the cell with notches or corrugations for the insertion of the cathode, adapted to fit tight to the cell. However, the objects pursued bvall these said known arrangements are entirely alien to the purpose aimed at by the present invention, the. ad-

vantages of which, when compared with the,

(liaphragnis hitherto in use, may be summed up as follows 1. The strength of the plate being the same, or even greater, a reduction in the wall-thickness, and hence, a reduction of strain and a corresponding saving of current.

2. In accordance with the said savin of current, a saving in cooling (1'. e., a re uction of Joules heat) in connection with numerous electrolyt-ical processes.

3. The external dimensions being the .same, an increase in the effective diaphragm having a central corrugated portion formed by concentrically arranged grooves, the edges of the diaphragm being plain and forming a strengthening edge.

In testimony whereof I have affixed my signature in presence of two witnesses.

RICHARD WALTER.

\Vitnesses R. LITSCHAUER, ARTHUR Lmonns'rnao. 

